An analysis of the literature and an essay on the problem of recognizing the diseases of workers — diagnosis and causation(work-relatedness assessment) are given. A historical reference is made on the etiology of workers’ diseases and the statements of the classics about the causality in medicine. The main categories of occupational medicine and terminology of the WHO and ILO, the principles of evidence in occupational health are considered. The WHO concept of work-related diseases (WRD), occupational disease (OD) recognition systems under ILO Convention No. 121, features of the ILO occupational diseases list (revision 2010), and the criteria for inclusion of diseases in this list are presented.The general provisions of causation, types of causation algorithms in consensus and evidence-based medicine, as well as a generalized algorithm for analyzing periodic medical examinations data are considered. The European experience of recognition of WRD is considered. Based on experience and literature data, we propose a 10-step causation algorithm, including forecasting the probability of OD and WRD, as well as quantifying the degree of work-relatedness with computer support programs from the electronic directory «Occupational Risk» (http://medtrud. com/). It is concluded that legal recognition of WRD is needed for early diagnosis and prophylaxis of workers’ health disorders in conditions of digitalization of the economy and society.